I find its interface really clunky and like a far cry from the Windows Vista era

Keep an eye out for https://github.com/kantord/LibreLingo - it is under development but looks really great

• Photoshop is certainly one - as much as I like Gimp, it is simply not as good as Photoshop, and that’s a reality. My friend does Architecture and her work would be an absolute chore on Gimp.
• Maybe even Adobe InDesign, Scribus just is not as good
• An actual good open source alternative to Premiere (I believe DaVinci Resolve is proprietary but correct me if I am wrong, but there is a free version that’s great)
• More towards the low level/firmware side, there still aren’t enough bootloaders and wireless cards drivers However, this is growing really quickly and are free in terms of free but not in terms of freedom!
• Obviously, actual competitors to Android/iOS which aren’t simply forks - I have hope for Ubuntu Touch. Again Android is technically free as far as I can tell, but I am talking about free in terms of freedom.
• Email clients and Calendar apps for Linux - Mailspring does not work with Protonmail and everything else looks as if it’s from the 1990s or doesn’t work well. I’m sticking with Thunderbird for now
• A good front-end wrapper or Facebook Messenger or - for example, I don’t use the Twitter or Reddit app, I use Twidere and Infinity, respectively , so something along those lines which isn’t simply the web page version in a container

I’ll probably add more as I think of them. Maybe I a non-electron code editor that can compete with VSCode/VSCodium that doesn’t require 10 days to configure and a lifetime to get used to (…vim/nvim)

Also, have you tried Draftsight for a dwg CAD?